U.S. patent number 11,421,465 [Application Number 16/852,021] was granted by the patent office on 2022-08-23 for actuator for powered vehicle closure.
This patent grant is currently assigned to STRATTEC POWER ACCESS LLC. The grantee listed for this patent is STRATTEC POWER ACCESS LLC. Invention is credited to Steven Buell, William Champ, Paul Crociata, Frederick Eberle, Jacob Fritschle, Howard Kuhlman, Kimpon Ngem, Daniel Sand, Brian Schymik, Gregory Sproule, David Wilcox, Michael Zientak.
United States Patent |
11,421,465 |
Sproule , et al. |
August 23, 2022 |
Actuator for powered vehicle closure
Abstract
A power closure actuator for powering a movable closure includes
an output member configured to drive movement of the movable
closure, a motor coupled through a gear reduction to drive the
output member, and an integrated brake-clutch unit having an input
configured to receive drive power from the electric motor. The
brake-clutch unit provides independent braking and clutching
between the electric motor and the output member via an electric
brake actuator and an electric clutch actuator, respectively. Brake
and clutch portions of the brake-clutch unit act on a rotor, and
brake force can be maintained on the rotor without powering the
brake actuator. A clutch disc is biased disengaged from the rotor.
The integrated brake-clutch unit provides a drive state between the
electric motor and the output member when the brake portion is
released concurrently with the clutch portion establishing a power
coupling between the clutch disc and the rotor.
Inventors: |
Sproule; Gregory (Linden,
MI), Kuhlman; Howard (Rochester Hills, MI), Eberle;
Frederick (Lake Orion, MI), Champ; William (Mount
Clemens, MI), Buell; Steven (Auburn Hills, MI),
Fritschle; Jacob (Rochester Hills, MI), Sand; Daniel
(Shelby Township, MI), Crociata; Paul (Farmington Hills,
MI), Wilcox; David (Kingston, MI), Schymik; Brian
(Rochester Hills, MI), Zientak; Michael (Shelby Township,
MI), Ngem; Kimpon (Grant Township, MI) |
Applicant: |
Name |
City |
State |
Country |
Type |
STRATTEC POWER ACCESS LLC |
Auburn Hills |
MI |
US |
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Assignee: |
STRATTEC POWER ACCESS LLC
(Auburn Hills, MI)
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Family
ID: |
1000006517091 |
Appl.
No.: |
16/852,021 |
Filed: |
April 17, 2020 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20200340282 A1 |
Oct 29, 2020 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62839268 |
Apr 26, 2019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16H
1/28 (20130101); F16D 7/00 (20130101); E05F
15/603 (20150115); F16D 67/02 (20130101); F16D
28/00 (20130101); E05Y 2400/45 (20130101); E05Y
2400/44 (20130101); B60J 5/101 (20130101); E05Y
2400/85 (20130101); E05Y 2900/50 (20130101); B60J
5/06 (20130101); E05Y 2201/21 (20130101); B60J
5/047 (20130101); B60J 5/108 (20130101); B62D
33/0273 (20130101); E05Y 2201/232 (20130101); E05Y
2201/434 (20130101) |
Current International
Class: |
E05F
11/00 (20060101); F16D 67/02 (20060101); F16H
1/28 (20060101); F16D 28/00 (20060101); E05F
15/603 (20150101); F16D 7/00 (20060101); B60J
5/04 (20060101); B62D 33/027 (20060101); B60J
5/10 (20060101); B60J 5/06 (20060101) |
Field of
Search: |
;49/340,341,339,324,349,334,348 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2551210 |
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Dec 2017 |
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GB |
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S6380330 |
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May 1988 |
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JP |
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2005226296 |
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Aug 2005 |
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JP |
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20110008674 |
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Jan 2011 |
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KR |
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Other References
Search Report issued from the European Patent Office for related
Application No. 20275078.2 dated Sep. 28, 2020 (5 Pages). cited by
applicant .
Communication issued from the European Patent Office for related
Application No. 20275078.2 dated Feb. 9, 2022 (5 Pages). cited by
applicant.
|
Primary Examiner: Nguyen; Chi Q
Attorney, Agent or Firm: Michael Best & Friedrich
LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application claims priority to U.S. Provisional Patent
Application No. 62/839,268, filed on Apr. 26, 2019, the entire
contents of which are incorporated by reference herein.
Claims
What is claimed is:
1. A power closure actuator for powering a movable closure, the
power closure actuator comprising: an output member configured to
drive movement of the movable closure; an electric motor coupled
through at least one gear reduction stage to drive the output
member; and an integrated brake-clutch unit having an input
configured to receive drive power from the electric motor, the
integrated brake-clutch unit providing independent braking and
clutching action between the electric motor and the output member
via an electric brake actuator and an electric clutch actuator,
respectively, wherein a brake portion of the integrated
brake-clutch unit includes a rotor having a first portion operable
to receive a brake force from a brake member in an absence of
electrical power to the electric brake actuator, wherein a clutch
portion of the integrated brake-clutch unit includes a clutch disc
rotatable with the input, the clutch disc selectively providing a
power coupling with a second portion of the rotor, the clutch disc
and the rotor being biased to a disengaged state in the absence of
electrical power to the electric clutch actuator, and wherein a
drive state between the electric motor and the output member is
established by release of the brake portion concurrently with the
clutch portion establishing the power coupling.
2. The power closure actuator of claim 1, wherein maintaining the
power coupling through the integrated brake-clutch unit for the
electric motor to power the output member is configured to require
continuous energization of both the electric brake actuator and the
electric clutch actuator to maintain a brake release force, and a
clutch coupling force between the clutch disc and the rotor,
respectively.
3. The power closure actuator of claim 2, wherein the electric
brake and clutch actuators are provided by first and second
electromagnetic coils mounted axially adjacent one another on a
common hub that is rotatably supported on an output shaft of the
integrated brake-clutch unit.
4. The power closure actuator of claim 1, wherein maintaining the
power coupling through the integrated brake-clutch unit for the
electric motor to power the output member is configured to require
continuous energization of the electric clutch actuator to maintain
a clutch coupling force between the clutch disc and the rotor, and
only momentary energization of the electric brake actuator to
release the brake force.
5. The power closure actuator of claim 4, wherein the integrated
brake-clutch unit includes a rotatable screw member driven by the
electric brake actuator, the screw member having a screw engagement
with the brake member such that the brake actuator is configured to
translate along a central axis of the integrated brake-clutch unit
in response to rotation of the screw member.
6. The power closure actuator of claim 5, wherein the screw member
is driven by a worm drive output of the electric brake actuator,
positioned off the central axis.
7. A vehicle having the movable closure, the power closure actuator
of claim 1, and a controller in communication therewith, the power
closure actuator further comprising a sensor providing an output
signal to the controller indicative of force applied to the movable
closure, wherein the controller is programmed to identify and
disregard a component of the output signal that is due to
inclination of the vehicle.
8. The vehicle of claim 7, wherein the sensor is incorporated in
the power closure actuator between the output member and a slip
clutch configured to limit torque transmission between the
integrated brake-clutch unit and the actuator output member to a
predetermined torque value.
9. The vehicle of claim 7, wherein the sensor generates the output
signal indicative of force applied to the movable closure by
detecting pressure, strain, or displacement between a housing of
the power closure actuator and a ring gear of a planetary gear
reduction stage retained within the housing.
10. The vehicle of claim 9, wherein the ring gear includes a
magnet, and the sensor includes a Hall effect circuit operable to
detect rotary motion of the ring gear within the housing.
11. A vehicle having movable closure, the power closure actuator of
claim 1, and a controller in communication therewith, the vehicle
further comprising at least one operator input device in the form
of a mechanical sensor or a touch sensor operable to provide a
signal to the controller for controlling the electric motor and
both of the electric brake and clutch actuators.
12. The vehicle of claim 11, wherein the at least one operator
input device is positioned on one or more of: the closure, a body
of the vehicle, a control panel within the vehicle, or a wireless
key fob.
13. The power closure actuator of claim 1, further comprising a
passive slip clutch configured to limit torque transmission between
the integrated brake-clutch unit and the actuator output member to
a predetermined torque value.
14. A method of powering a movable closure with a power closure
actuator, wherein an output member of the power closure actuator is
coupled to drive movement of the movable closure, the method
comprising: providing the power closure actuator in a first state,
wherein in the first state: an electric motor that provides the
driving force of the power closure actuator is off, a clutch disc
of an integrated brake-clutch unit provided between the electric
motor and the output member is biased to a disengaged state with
respect to a rotor of the integrated brake-clutch unit, and
electrical power to an electric clutch actuator that selectively
moves the clutch disc is absent, and a brake member, the movement
of the brake member being controlled by an electric brake actuator,
applies a brake force to the rotor while electrical power to the
electric brake actuator is absent; providing a first signal to a
controller to initiate powered movement of the movable closure with
the power closure actuator; in response to the first signal, the
controller providing a second signal to the electric clutch
actuator to establish a power coupling between the clutch disc and
the rotor, and providing a third signal to the electric brake
actuator to retract the brake member from the rotor to release the
brake force, thus putting the integrated brake-clutch unit into a
drive state; and with the integrated brake-clutch unit in the drive
state, the controller providing a fourth signal to energize the
electric motor so that driving force from the electric motor is
transferred through the integrated brake-clutch unit, and through
at least one gear reduction stage to the output member to open or
close the movable closure.
15. The method of claim 14 carried out on a vehicle having the
movable closure, wherein the first signal is provided from an
operator force sensor within the power closure actuator, and the
controller identifies and disregards a component of the first
signal that is due to gravitational force on the movable closure so
that a predetermined force for triggering the first signal
corresponds only to user-applied force on the closure, regardless
of vehicle inclination.
16. A power closure actuator for powering a movable closure on a
vehicle, the power closure actuator comprising: an electric motor
having an output; a controller in command of the electric motor; a
drivetrain provided between the motor output and an output member
of power closure actuator; a brake operable to selectively apply a
brake force to the drivetrain; and an operator force sensor
provided in the drivetrain and configured to detect a force on the
output member applied from the closure both due to gravitational
force on the closure resulting from vehicle inclination and due to
a user-applied force on the closure; wherein the controller is
configured to release the brake in response to the operator force
sensor detecting a value that corresponds to a force on the closure
at or above a predetermined force, the controller configured to
disregard the gravitational force so that the predetermined force
corresponds only to the user-applied force on the closure.
17. The power closure actuator of claim 16, wherein the brake is
part of an integrated brake-clutch unit having an input coupled to
the motor output.
18. The power closure actuator of claim 16, wherein the operator
force sensor includes at least one strain gauge, the controller
coupled to the at least one strain gauge and operable to segregate
an output of the at least one strain gauge into a first component
representing the user-applied force on the closure and a second
component representing the gravitational force to be
disregarded.
19. The power closure actuator of claim 16, wherein the operator
force sensor includes at least one pressure sensor, the controller
coupled to the at least one pressure sensor and operable to
segregate an output of the at least one pressure sensor into a
first component representing the user-applied force on the closure
and a second component representing the gravitational force to be
disregarded.
20. The vehicle of claim 19, wherein the at least one operator
input device is positioned on one or more of: the closure, a body
of the vehicle, a control panel within the vehicle, or a wireless
key fob.
21. The power closure actuator of claim 16, wherein the operator
force sensor includes an absolute position sensor, the controller
coupled to the absolute position sensor and operable to segregate
an output of the absolute position sensor into a first component
representing the user-applied force on the closure and a second
component representing the gravitational force to be
disregarded.
22. The power closure actuator of claim 16, wherein the operator
force sensor is situated between a rotary member and a sensor
housing to detect the gravitational and user-applied forces on the
closure, and wherein the rotary member forms a fixed ring gear of a
planetary gearset of the drivetrain.
23. A vehicle having the movable closure and the power closure
actuator of claim 16, the vehicle further comprising at least one
operator input device in the form of a mechanical sensor or a touch
sensor operable to provide a signal to the controller for
controlling the motor and the brake.
Description
BACKGROUND
The invention relates to powered vehicle closures and particularly
actuators provided for opening and/or closing a closure in an
automotive application including, but not limited to, truck end
gates or "tailgates," vehicular rear hatches, lift gates, trunks,
and side entry doors.
SUMMARY
In one aspect, the invention provides a power closure actuator for
powering a movable closure. The power closure actuator includes an
output member configured to drive movement of the movable closure,
an electric motor coupled through at least one gear reduction stage
to drive the output member, and an integrated brake-clutch unit.
The integrated brake-clutch unit has an input configured to receive
drive power from the electric motor. The integrated brake-clutch
unit provides independent braking and clutching action between the
electric motor and the output member via an electric brake actuator
and an electric clutch actuator, respectively. A brake portion of
the integrated brake-clutch unit includes a rotor having a first
portion operable to receive a brake force from a brake member in an
absence of electrical power to the electric brake actuator. A
clutch portion of the integrated brake-clutch unit includes a
clutch disc rotatable with the input, the clutch disc selectively
providing a power coupling with a second portion of the rotor, the
clutch disc and the rotor being biased to a disengaged state in the
absence of electrical power to the electric clutch actuator. The
integrated brake-clutch unit provides a drive state between the
electric motor and the output member when the brake portion is
released concurrently with the clutch portion establishing the
power coupling.
In yet another aspect, the invention provides a method of powering
a movable closure with a power closure actuator, an output member
of which is coupled to drive movement of the movable closure. The
power closure actuator is provided in a first state in which an
electric motor that provides the driving force of the power closure
actuator is off. In the first state, a clutch disc of an integrated
brake-clutch unit provided between the electric motor and the
output member is biased to a disengaged state with respect to a
rotor of the integrated brake-clutch unit, and electrical power to
an electric clutch actuator that selectively moves the clutch disc
is absent. Also, in the first state, a brake member, the movement
of which is controlled by an electric brake actuator, applies a
brake force to the rotor while electrical power to the electric
brake actuator is absent. A first signal is provided to a
controller to initiate powered movement of the movable closure with
the power closure actuator. In response to the first signal, the
controller provides a second signal to the electric clutch actuator
to establish a power coupling between the clutch disc and the
rotor, and provides a third signal to the electric brake actuator
to retract the brake member from the rotor to release the brake
force, thus putting the integrated brake-clutch unit into a drive
state. With the integrated brake-clutch unit in the drive state,
the controller provides a fourth signal to energize the electric
motor so that driving force from the electric motor is transferred
through the integrated brake-clutch unit, and through at least one
gear reduction stage to the output member to open or close the
movable closure.
In yet another aspect, the invention provides a power closure
actuator for powering a movable closure. The power closure actuator
includes an electric motor having an output, and a controller in
command of the motor. A drivetrain is provided between the motor
output and an output member of power closure actuator, the
drivetrain including a brake operable to selectively apply a brake
force to the drivetrain. An operator force sensor is provided in
the drivetrain and configured to detect a force on the output
member applied from the closure both due to gravitational force on
the closure resulting from vehicle inclination and due to a
user-applied force on the closure. A controller is configured to
release the brake in response to the operator force sensor
detecting a value that corresponds to a force on the closure at or
above a predetermined force, the controller configured to disregard
the gravitational force so that the predetermined force corresponds
only to the user-applied force on the closure.
Other aspects of the invention will become apparent by
consideration of the detailed description and accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a power closure actuator according
to one embodiment of the disclosure.
FIG. 2A is a cross-sectional view of the power closure actuator,
taken along line 2A-2A of FIG. 1.
FIG. 2B is a cross-sectional view of the power closure actuator,
taken along line 2B-2B of FIG. 1.
FIGS. 3A to 3H illustrate a variety of exemplary vehicular
installation applications for the power closure actuator of FIGS. 1
and 2, among other embodiments and variations thereof according to
the present disclosure.
FIG. 4A is a schematic view of a compact rotary variation of the
power closure actuator of FIGS. 1 to 2B.
FIG. 4B is a schematic view of an offset rotary variation of the
power closure actuator of FIGS. 1 to 2B.
FIG. 4C is a schematic view of an inline rotary variation of the
power closure actuator of FIGS. 1 to 2B.
FIG. 5 is a cross-sectional view of the power closure actuator,
taken along line 5-5 of FIG. 2A and illustrating a Hall Effect
sensor assembly.
FIG. 6 is a perspective view of an integrated brake-clutch unit,
removed from the power closure actuator of FIGS. 1 and 2.
FIG. 7A is a cross-sectional view of the integrated brake-clutch
unit in an at-rest operation state exhibiting passive braking.
FIG. 7B is a cross-sectional view of the integrated brake-clutch
unit in a free wheel operation state in which a brake coil is
energized to release the brake.
FIG. 7C is a cross-sectional view of the integrated brake-clutch
unit in a torque transferring drive state in which brake and clutch
coils are energized.
FIG. 8 is a cross-sectional view of the power closure actuator,
taken along line 8-8 of FIG. 2A and illustrating an operator force
sensor.
FIG. 8A is a perspective view of an operator force sensor according
to a first alternate embodiment.
FIG. 8B is a perspective view of an operator force sensor according
to a second alternate embodiment.
FIG. 8C is a perspective view of an operator force sensor according
to a third alternate embodiment.
FIG. 9 a perspective view of a slip clutch according to a first
embodiment.
FIG. 10 is a cross-sectional view of the slip clutch taken along
line 10-10 of FIG. 9.
FIG. 11 is an exploded assembly view of the slip clutch of FIGS. 9
and 10.
FIG. 12 is perspective view of a slip clutch according to a second
embodiment.
FIG. 13 is a cross-sectional view of the slip clutch taken along
line 13-13 of FIG. 12.
FIG. 14 is an exploded assembly view of the slip clutch of FIGS. 12
and 13.
FIG. 15 is a first perspective view of a brake-clutch unit
according to an alternate embodiment.
FIG. 16 is an alternate perspective view of the alternate
brake-clutch unit of FIG. 15.
FIG. 17 is cross-sectional view of the alternate brake-clutch unit,
taken along line 17-17 of FIG. 16.
FIG. 18 is a cross-sectional view of the alternate brake-clutch
unit, taken along line 18-18 of FIG. 16.
DETAILED DESCRIPTION
Before any embodiments of the present invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways.
FIGS. 1 to 2B illustrate a power closure actuator, or simply,
"actuator 20" which may be actuated to produce forces applied as
opening and/or closing forces for selectively opening and/or
closing a power closure such as a vehicle closure (e.g., a vehicle
entry door, hatch, tailgate or end gate, decklid or trunk, and the
like). The actuator 20 includes an electric motor 24 having an
output shaft, which in the illustrated construction is embodied as
a worm 28 operatively meshed with a worm gear 32 in a first gearbox
36. The first gearbox 36, along with several additional
subassemblies as described further herein, forms part of a
drivetrain between the motor 24 and an output shaft 40. The output
shaft 40, which is one exemplary form of an actuator output member,
defines a central axis A. The central axis A is shared with the
remainder of the drivetrain, aside from the motor 24 and the worm
28, although other constructions are optional as shown in FIGS. 4,
5, and 6. A linkage 44 is secured to the output shaft 40 and
operable by rotation of the output shaft 40 to perform an opening
and/or closing articulation. In the event that the actuator 20 is
supported to move with the closure, the linkage 44 can be secured
to the vehicle body structure (e.g., door frame, truck bed, or
pillar). However, in other constructions, the actuator 20 is fixed
to the vehicle body structure and the linkage 44 is secured to the
closure. The closure is selectively released from the vehicle body
by a separate latching device (not illustrated), which can be
powered or manually operable.
As illustrated in FIG. 3A, the actuator 20 is fixed to the vehicle
body structure (e.g., roof) and the linkage 44 is secured to the
closure 50, which is in the form of a liftgate. As illustrated in
FIG. 3B, the actuator 20 is fixed to the vehicle body structure and
the linkage 44 is secured to the closure 50, which is in the form
of a liftgate. As illustrated in FIG. 3C, the actuator 20 is fixed
to the closure 50, which is in the form of a liftgate, and the
linkage 44 is secured to the vehicle body structure. As illustrated
in FIG. 3D, the actuator 20 is fixed to the closure 50, which is in
the form of a sliding side door, and the linkage 44 is secured to
the vehicle body structure. As illustrated in FIG. 3E, the actuator
20 is fixed to the vehicle body structure (e.g., floor) and the
linkage 44 is secured to the closure 50, which is in the form of a
sliding side door. As illustrated in FIG. 3F, the actuator 20 is
fixed to the vehicle body structure (e.g., truck bed) and the
linkage 44 is secured to the closure 50, which is in the form of a
tailgate. As illustrated in FIG. 3G, the actuator 20 is fixed to
the closure 50, which is in the form of a tailgate, and the linkage
44 is secured to the vehicle body structure. As illustrated in FIG.
3H, the actuator 20 is fixed to the vehicle body structure and the
linkage 44 is secured to the closure 50, which is in the form of a
swinging side entry door, in particular a driver's side door.
Returning now to FIGS. 1 to 2B, the motor 24 of the actuator 20
defines a central axis of rotation B that is arranged at a skew
angle with respect to the central axis A. A housing 54 of the motor
24 is secured to a first intermediate housing 58, also forming the
housing of the first gearbox 36. The first intermediate housing 58
is in turn secured to a second intermediate housing 62 containing
an electromagnetic brake with integrated clutch (EMBIC) unit 66 and
a slip clutch 70. The second intermediate housing 62 is in turn
secured to an output housing or cap 80, also forming the housing of
a second gearbox 76. The various housings 54, 58, 62, 80 can be
secured to each other in various ways, for example by interfacing
flanges with a plurality of threaded fasteners. One or both of the
first and second gearboxes 36, 76 can include a planetary gear set.
The second intermediate housing 62 can have opposing axial ends
sandwiched axially between the first intermediate housing 58 and
the output housing 80. The output housing 80 surrounds a portion of
the output shaft 40 and is secured to a distal end (opposite the
motor 24) of the second intermediate housing 62 (e.g., with a
plurality of threaded fasteners). Any or all of the housing
attachments can be made by alternate means besides threaded
fasteners, either in lieu of or in addition to threaded fasteners.
The output shaft 40 is supported for rotation by one or multiple
bearings 84, for example rolling element bearings, along its
length. Additional sections of the drivetrain are supported for
rotation by additional bearings in any or all of the aforementioned
housings.
In general functional terms, the motor 24 provides input torque in
a prescribed direction for opening or closing the closure 50 to one
or more gear reduction stages (e.g., of the first gearbox 36), an
output of which transmits an amplified torque (at reduced speed) to
an input of the EMBIC unit 66. The EMBIC unit 66 controls whether
or not a driving connection is established between the motor 24 and
the output shaft 40, and more particularly between the first
gearbox 36 and the slip clutch 70. As a separate function, the
EMBIC unit 66 also controls whether or not a braking force is
applied on the drivetrain. Specific functions of the EMBIC unit 66
are covered in further detail below with reference to FIGS. 7A to
7C. Regardless of the state of the EMBIC unit 66, the slip clutch
70 provides a fully passive mechanism limiting abusive loads from
being transmitted to the components of the drivetrain, including
the motor 24 and the various gear reduction stages. The slip clutch
70, as described in further detail below with reference to FIGS. 9
to 11, transmits torque only up to a prescribed torque threshold
and automatically slips to break the continuity of the drivetrain
above the prescribed torque threshold. As shown in the
cross-section of FIG. 5, a magnet (e.g., magnet ring 88A) and Hall
sensor 88B form a Hall sensor assembly 88 operable to detect
rotational position change (e.g., on an output side of the slip
clutch 70) of the drivetrain during operation. The Hall sensor
assembly 88 is one example of a position sensor, although others
may be appreciated as suitable replacements, that can detect
position and/or speed of the output shaft 40 or other components of
the drivetrain having a fixed relationship therewith (i.e.,
downstream of the EMBIC unit 66 and the slip clutch 70).
Additionally noted in FIG. 1 is the location of an operator force
sensor 92, which is described in further detail below with
reference to the cross-section of FIG. 8. The sensor 92 is
incorporated into the drivetrain downstream of the slip clutch 70,
for example within the second gearbox 76, although the operator
force sensor 92 is located in other locations in alternate
constructions. In a working closure application of the actuator 20
in which the actuator 20 operates to perform a power open and/or
power close function for the closure 50, such a system additionally
includes a controller 96 in signal communication with the motor 24,
the EMBIC unit 66, the Hall sensor assembly 88, and the operator
force sensor 92. The controller 96 can be integrated into the
actuator 20 or provided elsewhere within a vehicle. The controller
96, which can include a microprocessor and memory for storing
executable instructions, can be implemented in whole or part as a
vehicle body control module or may be in signal communication with
a body control module.
Through the EMBIC unit 66, the actuator 20 can exhibit three
distinct drivetrain states including: drive, neutral (or
"freewheel"), and brake as shown in FIGS. 7A to 7C. In the drive
state, input and output sides of the EMBIC unit 66 are connected
for driving. The at-rest (i.e., no power) state of the EMBIC unit
66 is a state in which the brake is engaged and the clutch is
disengaged. Thus, transition from the at-rest state to the drive
state involves actuating two separate internal actuators of the
EMBIC unit 66, the first actuator being an electromagnetic brake
coil 104, and the second actuator being an electromagnetic clutch
coil 108. Because the at-rest state is the brake state, the EMBIC
unit 66 passively (without any supply of power) holds the output
shaft 40, and thus the closure 50, fixed in a given position. Thus,
the EMBIC unit 66, along with the controller 96, enables an
infinite check/stop and hold feature for the closure 50 in any
position throughout the movement range of the closure 50, rather
than relying on fixed-position detents (e.g., typical door detents
used to hold a vehicle entry door in one of a few preselected
positions). The passive nature of the EMBIC unit brake avoids
electrical power drain (e.g., from a main vehicle battery that
powers the actuator 20) in the event the operator desires to leave
the closure 50 in a partly or fully open state for a length of time
(e.g., during loading/unloading). The brake of the EMBIC unit 66
may also provide a stronger holding force than conventional door
detents in some constructions such that the closure 50 is less
likely to move from the desired position (e.g., by wind or other
incidental forces). During times of powered output from the motor
24 to the output shaft 40 for power opening or power closing, the
brake coil 104 is actuated to release the brake and the clutch coil
108 is actuated to close/couple the clutch. The EMBIC unit 66 of
the illustrated embodiment is constructed according to the
following description, although other embodiments are envisioned,
including but not limited to those shown in FIGS. 4B and 4C, shown
in the drawings alongside a schematic representation (FIG. 4A) of
the actuator 20 according to the construction of FIGS. 1 to 2B. In
the variation of FIG. 4B, the central axis is broken into two
parallel axes A, A' with a connecting drivetrain 75 between the
components on the respective axes (e.g., additional transfer gears,
belt, chain, etc.). FIG. 4C illustrates a construction in which the
motor 24 that acts as the seminal drive source of the actuator 20
is arranged with its axis along the same axis as the EMBIC unit 66,
the output shaft 40, and the other components therebetween. Thus,
aspects of the present disclosure may be adapted to various package
sizes and shapes as necessary to meet the needs of a particular
closure application.
Referring particularly to FIGS. 6 to 7C, an input member 112 and an
output shaft 114 are concentrically arranged along the central axis
A of the EMBIC unit 66. Although a portion of the output shaft 114
is received through the entire EMBIC unit 66 and through a hollow
portion of the input member 112, there is no driving connection
directly from the input member 112 to the output shaft 114. The
input member 112 can be formed as an axially extended portion of a
gear of the gearbox 36. A clutch member, particularly clutch disc
116, is secured to the input member 112 for rotation therewith. For
example, a flange portion of the input member 112 can be bonded,
pinned, screwed, etc. together with an axial end wall of the clutch
disc 116. The clutch disc 116 is arranged to form one axial end of
a body of the EMBIC unit 66, which can be cylindrical in shape. A
radially outer portion of the clutch disc 116 can include an axial
extension portion that extends toward an output end (left as shown)
of the EMBIC unit 66. A rotor member, particularly rotor disc 118,
is fixed for rotation with the output shaft 114, e.g., by spline,
key, bonding, etc. As illustrated, a radially inner portion of the
rotor disc 118 can include an axial extension portion that extends
toward the output end of the EMBIC unit 66. A hub 120 extends at
least partially around the rotor disc 118 (e.g., axial extension
portion of the rotor disc 118) and supports the brake and clutch
coils 104, 108. Radial clearance may be provided between the rotor
disc 118 and the radially surrounding portion of the hub 120. The
hub 120 is arranged to form the other axial end of the EMBIC unit
body, opposite the clutch disc 116. A bearing 130 supports the hub
120 on the output shaft 114, and the hub 120 is also maintained out
of engagement with the clutch disc 116. Thus, the hub 120 is
rotatably separate from both the EMBIC unit output (provided
cooperatively by the output shaft 114 and the rotor disc 118) and
the EMBIC unit input (provided cooperatively by the input member
112 and the clutch disc 116).
A brake member, particularly a brake sleeve 124, radially surrounds
at least a portion of the brake coil 104. The brake sleeve 124 is
slidably supported on a guide 125. The guide 125, which has a
T-shaped cross section on each side of the axis A, also acts to
direct the required magnetic flux for the electromagnetic coil(s)
104, 108. The brake sleeve 124 is positioned axially between a
radial flange portion of the hub 120 and the rotor disc 118. The
brake sleeve 124 is biased toward the input end of the EMBIC unit
66 (right as shown, and thus toward the clutch disc 116 and away
from the hub 120) by one or more brake springs 122 positioned
between the hub 120 and the brake sleeve 124. The bias force from
the brake spring 122 urges the brake sleeve 124 against the rotor
disc 118, particularly a first axial end surface thereof as shown.
For example, the brake sleeve 124 may press upon the first portion
of the rotor disc 118 through one or more friction discs 126.
Because the rotor disc 118 is fixed for rotation with the output
shaft 114, the output shaft 114 is thus braked by the brake sleeve
124 from the force in the brake spring 122. Thus, the brake spring
122 maintains brake engagement at-rest in a state in which there is
no power draw by the brake coil 104, or more broadly no power being
supplied to the actuator 120 overall. Electrical current powering
the brake coil 104 causes the brake sleeve 124 to be attracted to
the brake coil 104, urging the brake sleeve 124 to overcome the
bias of the brake spring 122 and release the brake as shown in FIG.
7B (e.g., by releasing the friction discs 126). This converts the
EMBIC unit 66 from the at-rest brake state to the neutral or
freewheel state. Under circumstances that the controller 96
determines that the EMBIC unit 66 is to be bypassed so that the
closure 50 can be freely opened and closed by the user rather than
under power of the motor 24, the brake coil 104 is energized to
achieve the neutral state of FIG. 7B. In the neutral state, a human
operator can open and close the closure 50 without resistance of
the actuator 20 (i.e., with the feel of a conventional un-powered
closure).
With respect to the clutch, the rotor disc 118 has a portion (e.g.,
a second axial end surface) defining a friction surface in
selective contact with a mating and co-facing friction surface of
the clutch disc 116 to close/couple the clutch of the EMBIC unit
66. A clutch spring 128 normally biases the two mating friction
surfaces of the clutch disc 116 and the rotor disc 118 apart from
each other, for example defining an axial space therebetween, so
that the clutch is open or decoupled and torque is not
transferrable from the input member 112 and the clutch disc 116 to
the rotor disc 118 and the output shaft 114. Electrical current
powering the clutch coil 108 causes the clutch disc 116 to be
attracted to the clutch coil 108 (right as shown, same attraction
direction as the brake coil 104 on the brake sleeve 124) to
overcome the bias of the clutch spring 128 and close/couple the
clutch by bringing the friction surfaces of the clutch disc 116 and
the rotor disc 118 together. The clutch disc 116 may move alone or
the input member 112 may move with the clutch disc 116. Under
circumstances that the controller 96 determines that the motor 24
is to drive the output shaft 40 through the EMBIC unit 66 to
perform a powered opening or powered closing of the closure 50, the
brake coil 104 is energized to release the brake and concurrently
the clutch coil 108 is energized to close/couple the clutch and
achieve the drive state of FIG. 7C. This state of the EMBIC unit 66
is maintained throughout operation of the motor 24 to perform the
powered opening or the powered closing.
In use of the closure 50, for example on a vehicle, the vehicle
operator may provide an input to a designated input device 132, for
example a mechanical sensor (e.g., button, switch, dial, etc.
either integrated with or separate from a handle on the closure 50)
or a touch sensor (e.g., a touch pad or touch screen having
resistive or capacitive sensing). The operator input device 132 can
be one of a plurality of operator input devices 132, and the
operator input device(s) can be positioned on the closure 50, on
the vehicle body, on a control panel of the vehicle interior,
and/or on a vehicle key fob having a wireless connection to the
vehicle. Example operator input devices 132 are shown throughout
FIGS. 3A to 3H. The input can be received by the controller 96, for
example, via one or more signals from any one of the above
mentioned input devices, and in response the controller 96 can
signal the brake coil 104 to power off and release the EMBIC unit
brake 66. Depending on the controller logic and/or the type of
input from the operator, the EMBIC unit 66 can either remain in the
neutral state, or further be actuated to establish the drive state
by a signal from the controller 96 to power on the clutch coil 108.
In addition to the operator input mechanisms described above, the
actuator 20 can further be configured to respond (i.e., perform a
change of state such as a change of state of the EMBIC unit 66
and/or a change in motor operation such as speed and/or direction)
to an operator force applied to the closure 50, in particular a
pushing or pulling force in the opening or closing direction of the
closure 50. However, enabling the actuator 20 via the controller 96
to make an appropriate determination for response is significantly
challenged by the potentially diverse static conditions of the
vehicle. In particular, a vehicle having the closure 50 cannot
reasonably be expected to have use only in a flat or level
orientation with respect to earth. Rather, normal use of the
vehicle will typically include various states of pitch in which the
front of the vehicle is higher or lower than the rear, and roll in
which the left side of the vehicle is higher or lower than the
right side. In the context of this application, pitch and roll do
not refer to dynamic motion of the vehicle, but rather the static
inclination of the vehicle having the vehicle closure 50, as
considered with respect to earth.
To overcome the above mentioned difficulties, the actuator 20
includes force sensing capability that enables the controller 96 to
differentiate force on the closure 50 applied by an operator, i.e.,
a human user, from force on the closure 50 applied by gravitational
forces on the closure 50 in the opening/closing direction of the
closure 50 due to vehicle inclination. Thus, the response of the
actuator 20 to user-applied force on the closure 50 is independent
of vehicle inclination so as to provide consistent and repeatable
effort for the user. The force sensing referred to above utilizes
the operator force sensor 92 briefly introduced above with respect
to FIG. 1. A first exemplary embodiment of the operator force
sensor 92 is shown in further detail in FIG. 8. As shown there, the
sensor 92 includes a housing, either a separate housing or in this
case a portion of the end housing 80. A rotary element 138 is
positioned within the housing 80. Although the rotary element 138
may have limited rotational freedom within the housing 80, the
rotary element 138 forms an otherwise fixed component (e.g., ring
gear) of a gear reduction stage (e.g., planetary gear set) in the
second gearbox 76. In particular, the housing 80 and the rotary
element 138 are engaged with complementary shapes that allow only a
limited amount of relative rotation therebetween (e.g., less than
20 degrees, or less than 15 degrees). For example, as illustrated,
the inside of the housing 80 and the outside of the rotary element
138 form a spline engagement that is loose-fitting, having
intentional circumferential clearance between mating spline
portions. The housing 80 that houses the sensor 92 may be fixed to
or integral with the other actuator housing(s) 54, 58, 62. The
rotary element 138 includes at least one radial protuberance 138A
received in a radial extension space or cavity 136 of the housing
80. The illustrated construction includes two such protuberances
138A, diametrically opposed. One or more springs 142 are arranged
against each radial protuberance 138A in the cavity 136. In the
illustrated example, each spring 142 forms a loop from which two
legs extend so that one leg is positioned on each side of the
radial protuberance 138A of the rotary element 138. The springs 142
can be secured to and/or retained by a spring housing 144 within or
extended from the cavity 136. As shown in FIG. 2A, each spring 142
is held within a spring housing 144 formed in the adjacent second
intermediate housing 62. The springs 142 urge the rotary element
138 to a central position within its limited range of rotational
travel in the housing 80 so that it has available travel in both
directions with respect to the housing 80. However, in response to
forces, more particularly torque in a rotational application,
applied to the output shaft 40 (e.g., when the EMBIC unit 66 is in
the braked state), the rotary element 138 of the operator force
sensor 92 may rotate with respect to the housing 80. In other
words, the operator force sensor 92 is located in the drivetrain at
a position downstream of the brake of the EMBIC unit 66.
The operator force sensor 92 is an absolute position sensor. The
sensor 92 is operable to track the position of the radial
protuberance 138A of the rotary element 138, such as the deviation
from a central position as biased by the springs 142. The sensor 92
can be implemented as a Hall effect sensor assembly including a
Hall effect sensor element (i.e., circuit) 148 secured to the
housing 80 and a magnet 150 secured to the rotary element 138. The
sensor element 150 can be located at least partially within a
radial extension space or cavity 146 separate from the cavities 136
in which the biased radial protuberances 138A are located, and the
magnet 150 can be supported on or in a portion (e.g., optionally
radially protruded, and optionally extending into the cavity 146)
of the rotary element 138 separate from the biased radial
protuberances 138A. The sensor element 148 provides an output is in
communication with the controller 96 and operable to detect torque
in the drivetrain resulting from applied force on the closure 50
(e.g., by a human user pushing or pulling on the closure 50).
Gravitational force in the opening-closing direction of the closure
50 is also sensed by the sensor element 148, but the gravitational
component is configured to be segregated and neglected so that
uniformity can be provided in effort on the closure to achieve a
prescribed response of the actuator 20. In other words, for a car
door or other closure, its own weight will not add to or subtract
from the needed operator effort to trigger the controller threshold
for operating the actuator 20. The controller 96 may for example
perform a time-based comparison of output signal(s) from the sensor
element 148 in order to identify an output signal change
corresponding to the change in force or "force delta" applied from
the closure 50 to the operator force sensor 92. The initial or
static signal from the sensor element 148 is categorized as
gravitational force (if any) due to inclination, and this amount,
which is either positive or negative due to its directional nature,
is subtracted from a subsequent force measurement of the sensor
element 148. In some constructions, the segregation of forces can
be confirmed or accomplished via an inclinometer on board the
vehicle and provided in communication with the controller 96. For
example, if the controller 96 is programmed with an algorithm that
takes into consideration a mass of the closure, then inclination
data can be used to calculate a gravitational force that the
closure imparts to the actuator 20 at the output shaft 40.
A prescribed response of the actuator 20 can be a release of the
brake and/or release of the brake, coupling of the clutch, and
actuation of the motor 24, and/or if the motor 24 is already
operating, changing speeds of the motor 24, including stopping of
the motor 24. In an example where the motor 24 is running, the
controller 96, on the basis of the operator force sensor 92, may
slow down the motor speed when operator force is applied to the
closure 50 in a direction opposite the motor-driven direction
and/or the controller 96, on the basis of the operator force sensor
92, may speed up the motor speed or transition to the neutral state
of the drivetrain when operator force is applied to the closure 50
in the motor-driven direction. Although these operations are
available for utilizing the operator force sensor 92, the
controller logic may utilize less than all of these potential
operations, or may use certain operations in conjunction with or as
a back-up to another sensor or primary controller logic. For
example, the actuator 20 can include a separate position sensor,
rotary encoder or the like (e.g., the Hall sensor assembly 88) that
enables the controller 96 to track the relationship between speed
and electric current to the motor 24, and this speed/current
relationship is utilized as the primary means to detect and respond
to forces applied to the closure 50 during powered open/close
operations by the motor 24.
FIG. 8A illustrates another operator force sensor 92' generally
similar to the operator force sensor 92 except as otherwise noted.
In this construction, there is a single radial protuberance 138A,
which both carries the magnet 150 and is directly biased by the
springs 142'. Thus, the housing 80' includes only one radial cavity
136 to accommodate the entire operator force sensor 92'. The
springs 142' in this construction are coil springs arranged along
an axis perpendicular to a radial line from the axis A (although
both springs 142' are offset from this radial line, such that the
springs 142' are not arranged exactly tangential). Various spring
types and arrangements may be utilized. A spring pocket 144 extends
as a sub-cavity from the cavity 136 on each side of the radial
protuberance 138A.
FIG. 8B illustrates an operator force sensor 292 according to
another exemplary construction that can be incorporated in the
actuator 20. Like the sensor 92 of FIG. 8, the operator force
sensor 292 includes a housing 280 and a rotary element 238. In
particular, reference is made to the above description of the
operator force sensors 92, 92', particularly the basic
configuration of the housing 236 and the rotary element 238, which
are most similar to those of FIG. 8A. However, rather than having a
Hall effect sensor element coupled with the controller 96 and
operable to obtain a measure of torque, the operator force sensor
292 includes sensor elements 248 in the form of pressure sensors
situated between the housing 280 and the rotary element 238 (e.g.,
flanking the radial protuberance 238A of the rotary element 238 in
the corresponding cavity 236 of the housing 280) to obtain a
measure of torque applied therebetween. Although referred to herein
as the rotary element 238, it should be noted that the
configuration of the operator force sensor 292 may provide very
little clearance and minimal or no measurable rotation of the
rotary element 238. Thus, the term rotary element within the
context of an operator force sensor may refer to the fact that the
element is not directly restrained by or fixed to the housing 280
such that torque exerted on the rotary element 238 is borne by the
sensor elements 248 and not directly reacted by the housing 280. In
other words, the sensor elements 248 are operatively positioned
between the housing 280 and the rotary element 238 so as to observe
such torque.
FIG. 8C illustrates an operator force sensor 392 according to
another exemplary construction that can be incorporated in the
actuator 20. Like the sensor 92 of FIG. 8, the operator force
sensor 392 includes a housing 380 and a rotary element 338. In
particular, reference is made to the above description of the
operator force sensors 92, 92', 292 with respect to the basic
configuration of the housing 380 and the rotary element 338.
However, rather than having a Hall effect sensor element or
pressure sensors coupled with the controller 96 and operable to
obtain a measure of torque, the operator force sensor 392 includes
sensor elements 348 in the form of strain gauges (i.e., strain
gauge circuits) situated on the spring(s) 342 that bias the rotary
element 338 with respect to the housing 380 (e.g., centering the
radial protuberance 338A in the cavity 336). The springs 342 can be
linear springs, each having at least one surface that experiences
strain (measurable elastic deformation) during rotary displacement
of the rotary element 338. The spring surfaces having the strain
gauges 342 mounted thereon can be flat surfaces. The strain
measured correlates to torque applied therebetween. Because the
sensor elements 348 are integrated with the springs 342, the
additional housing cavity 146 is not required.
Thus, regardless of the exact type of sensor element(s) or
transducer(s) (e.g., strain gauge, pressure sensor, Hall effect or
other position detector, etc.), the operator force sensors 92, 92',
292 are torque sensors configured to detect torque resulting from
operator force applied in the opening/closing direction of the
closure 50.
Turning to FIGS. 9-11, the slip clutch 70 of the power closure
actuator drivetrain is shown in further detail. As shown, the slip
clutch 70 includes an input shaft 114, a housing 156, and an output
shaft 158. Although referred to as the input shaft 114 with respect
to the description of the slip clutch 70, the input shaft 114 can
be the same shaft as the output shaft 114 of the EMBIC unit 66,
either provided as a single monolithic element, or separate
elements fixedly secured to rotate together. The housing 156 may be
of plastic material construction. The input shaft 114 extends out
of a first end of the housing 156. The input shaft 114 may have a
fixed rotational relationship with the motor 24, at least when the
EMBIC unit 66 is in the driving state. When there is no slip in the
slip clutch 70 (i.e., torque between the input and output shafts
114, 158 does not exceed a threshold amount), the input and output
shafts 114, 158 also have a fixed rotational relationship and in
fact rotate together as one. However, there is no
torque-transmitting connection or engagement directly between the
input shaft 114 and the output shaft 158. The shafts 114, 158 may
have no direct interface therebetween. In other constructions (see
FIG. 13), the interface between the shafts 114, 158 is a rotational
journal interface by which an end of the input shaft 114 is
rotatably supported in an aperture formed in the output shaft 158
or vice versa. A clutch pack forms the torque-transmitting
connection between the input of the slip clutch 70 (e.g., the input
shaft 114 of the illustrated construction) and the output of the
slip clutch 70 (e.g., collectively defined by the housing 156 and
the output shaft 158 in the illustrated construction). The housing
156 and the output shaft 158 in all circumstances rotate together
as one, for example being splined or keyed together, manufactured
integrally, etc. The threshold torque that induces slip between the
input and output shafts 114, 158 is determined by the clutch pack,
which includes integral preload springs. The slip clutch 70
includes two sets of clutch members or discs, including stationary
plates in the form of flat washers 178 and rotating clutch members
in the form of Belleville disc springs 180. So that similar contact
is established between each flat washer to Belleville disc spring
interface, each Belleville disc spring 180 is arranged to have the
outer perimeter thereof in contact with the adjacent flat washer
178. As such, there are two Belleville disc springs 180 positioned
between each adjacent pair of flat washers 178. The flat washers
178 have an outer perimeter shaped complementary to an inner
periphery of the housing 156 so that the flat washers 178 are
rotationally locked to the housing 156. On the other hand, the
Belleville disc springs 180 have a non-circular inner periphery
(e.g., two opposing flat sides 180A forming a "double-D" shape)
complementary to the outer surface of the clutch input, which in
the slip clutch 70 is cooperatively formed by the input shaft 114
and a bushing 184 fixed therewith. One or more apertures 178A in
the flat washers 178 (e.g., positioned at the radial distance of
the point of contact with the Belleville disc springs 180) can
contain a quantity of grease for lubricating the mating friction
surfaces of the slip clutch 70. As shown, each of the three flat
washers 178 includes three equally-spaced grease-containing
apertures 178A. In other constructions, the slip clutch 70 is a dry
clutch in which the clutch pack is not bathed in oil or lubricated
with grease. A nut 170 is threaded onto the bushing 184 to set the
preload in the clutch pack by at least partially deflecting the
Belleville disc springs 180. The nut 170 thusly provides
adjustability or the ability to tune the torque transmission limit
of the slip clutch 70. However, the nut 170 may be utilized only in
initial manufacturing and/or testing, and may subsequently be
crimped or otherwise permanently fixed to the input shaft 114 so
that the clutch preload is fixed for the useful life of the
actuator 20. Although other configurations are optional, the
Belleville disc spring 180 on one axial end of the clutch pack is
in direct contact with the nut 170, and the Belleville disc spring
180 on the opposite axial end of the clutch pack is in direct
contact with an axial end surface within the housing 156. During
operation, when net torque between the input and output sides,
applied in either direction, exceeds the prescribed threshold,
frictional forces between the flat washers 178 and the Belleville
disc springs 180 are overcome and the excess torque is not
transmitted, thus protecting the mechanical components of the
drivetrain from exposure to such torque.
FIGS. 12-14 illustrate a slip clutch 70' according to another
exemplary embodiment. The slip clutch 70' performs the same
function as the slip clutch 70 in the drivetrain of the actuator
20, and thus the following description of the slip clutch 70' is
focused on aspects of the construction that differ from the slip
clutch 70 of FIGS. 9-11. Like reference numbers are used where
applicable. In the slip clutch 70', rather than the clutch pack
including integral preload springs, a separate clutch spring 166 is
provided to bear on the clutch pack. In particular, the alternating
sets of clutch members or discs, particularly stationary wear
plates 162 and rotating wear plates 164 with friction discs 163
therebetween. The clutch spring 166 exerts a bias force on the
clutch pack and presses an axial end of the clutch pack against an
axially abutting interior surface of the housing 156. The clutch
spring 166 is embodied here as one or more wave springs, but
various types of springs may be used in alternate constructions.
Each of the stationary wear plates 162 is nested into the housing
156 so as to be rotationally locked therewith. Each of the rotating
wear plates 164 is rotationally locked with the input shaft 114. As
illustrated, the rotating wear plates 164 have a star-shaped
central aperture for mating engagement with a star-shaped outer
profile of the bushing 184' that is rotationally locked with the
input shaft 114 (e.g., splined or keyed therewith). The stationary
and rotating wear plates 162, 164 are in frictional contact through
the intervening friction discs 163. As with the clutch 70, the nut
170 can be permanently fixed once the preload is set prior to final
assembly of the actuator 20. The nut 170 of the slip clutch 70' is
threaded onto the input shaft 114 and is operable to indirectly
(e.g., via a washer 172) exert a preload on the clutch pack to
squeeze the wear plates 162, 164 and the friction discs 163
together. Although not shown, the housing 156 can have a
multi-piece construction, for example, including a separate end cap
to cooperate to close the open end of the housing 156 where the nut
170 is located. As mentioned briefly above, the input shaft 114 has
a reduced diameter end portion 114A that is rotatably received
within a concentric end bore 158A of the output shaft 158 such that
a journal bearing is provided therebetween--there being no torque
transmitted here between the shafts 114, 158.
The EMBIC unit 66 of the preceding disclosure is one example of an
integrated brake-clutch unit, particularly one in which both the
brake and clutch functions are achieved through electromagnetic
coils. However, FIGS. 15-18 illustrate another embodiment of an
integrated brake-clutch unit 266 that is operable as a replacement
for the EMBIC 66 in the actuator 20 of the preceding disclosure.
Similar to the EMBIC 66, the brake-clutch unit 266 of FIGS. 15-18
requires actuation of both the brake and clutch portions in order
to establish a driving connection. As such, the actuator 20 can
exhibit three distinct drivetrain states including: drive, neutral
(or "freewheel"), and brake according to the corresponding states
of the brake-clutch unit 266. In the drive state, input and output
sides of the brake-clutch unit 266 are connected for driving.
Transition from the at-rest state to the drive state may involve
actuating two separate actuators of the brake-clutch unit 266, the
first actuator being a brake actuator 204 (e.g., electric motor
with worm drive output 204A), and the second actuator being an
electromagnetic clutch coil 208 similar to the coil 108 of the
EMBIC unit 66. Like the EMBIC unit 66, the brake-clutch unit 266
can have an at-rest state in which the brake is engaged so that the
brake-clutch unit 266 passively (without any supply of power) holds
the output shaft 40, and thus the closure 50, fixed in a given
position. To enable powered output from the motor 24 to the output
shaft 40 for power opening or power closing, the brake actuator 204
is actuated to release the brake, and the clutch coil 208 is
actuated to close/couple the clutch. As such, similar benefits as
those of the EMBIC unit 66 may be enjoyed. However, the brake
portion of the brake-clutch unit 266 is equipped to be bi-stable
rather than biased in one direction to the brake-engaged state.
Thus, the brake-clutch unit 266 can have a second at-rest state in
which the clutch is open or decoupled to be in a
non-torque-transmitting state, and the brake is left disengaged
without continuous actuation of the brake actuator 204. In such a
state, the actuator 20 is imperceptible to the user in that it
poses no added interference or obstruction to the user manually
operating the attached closure. The brake-clutch unit 266 of the
illustrated embodiment is constructed according to the following
description, although other embodiments are envisioned.
Concentrically arranged along the central axis A of the
brake-clutch unit 266 are an input member 212 and an output shaft
214. Although a portion of the output shaft 214 is received within
the hollow input member 212, there is no driving connection
directly therebetween. A clutch member, particularly clutch disc
216, is secured to the input member 212 for rotation therewith. The
clutch disc 216 is arranged to form one axial end of a body of the
brake-clutch unit 266, which can be cylindrical in shape. A rotor
member, particularly rotor disc 218, is fixed for rotation with the
output shaft 214, e.g., by spline, key, bonding, etc. As
illustrated, both a radially outer portion and a radially inner
portion of the rotor disc 218 can extend axially toward the output
end of the brake-clutch unit 266. A hub 220 is situated at least
partially around the axially-extended inner portion of the rotor
disc 218 and supports the clutch coil 208. Radial clearance may be
provided between the rotor disc 218 and the radially surrounding
portion of the hub 220. The hub 220 is coupled with extension arms
of a guide housing 225 that forms the other axial end of the
brake-clutch unit body, opposite the clutch disc 216. The guide
housing 225 also supports the brake actuator 204, which is
positioned away from the axis A. The hub 220 is maintained out of
engagement with the rotor disc 218. Thus, the hub 220 is rotatably
separate from both the input and the output of the brake-clutch
unit output.
A brake member, particularly brake sleeve 224, is arranged about
and movable along the axis A. The brake sleeve 224 can be guided
for axial movement by the guide housing 225, although a guide pin
227 is also shown extending from the hub 220 through a guide
aperture 229 in the brake sleeve 224. A friction member (e.g.,
disc) 226 is provided on one or both of the brake sleeve 224 and a
corresponding contact portion of the rotor disc 218 such that the
friction member 226 receives an axial pressing force for braking
the rotor disc 218 and the output shaft 214 when the brake is in
the actuated position (closing the gap which is shown in FIG. 18).
The brake sleeve 224 is unbiased, thus eliminating the brake spring
122 of the prior embodiment. Rather, a screw member 235 is engaged
with the brake sleeve 224 such that rotation of the screw member
235 about the axis A, which is driven by the worm drive output 204A
through a gear portion of the screw member 235, drives the brake
sleeve 224 which acts as a lead screw nut guided by the guide
housing 225 and the guide pin 227. The screw member 235 is
rotatably supported on the output shaft 214 by one or more
bearings. The brake actuator 204 is not back-drivable through the
worm drive output 204A, thus the brake will remain in the
brake-engaged state even without continued energization of the
brake actuator 204, following an actuation to the brake-engaged
state. Reverse actuation of the brake actuator 204 causes reverse
rotation of the screw member 235 and reverse axial movement of the
brake sleeve 224 to disengage the rotor disc 218 and release the
brake as best shown in FIG. 18. As long as the clutch remains
unactuated, the brake release converts the brake-clutch unit 266
from the brake state to the neutral or freewheel state, both of
which are at-rest or de-energized states of the actuator 20. Under
circumstances that the controller 96 determines that the
brake-clutch unit 266 is to be bypassed so that the closure 50 can
be freely opened and closed by the user rather than under power of
the motor 24, the brake is released to achieve the neutral state,
and this is accomplished by a momentary, rather than continuous,
energization of the brake actuator 204.
In order to use the power of the actuator 20 to operate an attached
closure, a power coupling must be established through the
brake-clutch unit 266 by engaging the clutch portion thereof. With
respect to the clutch, the rotor disc 218 has a portion (e.g., a
second axial end surface opposite that of the brake-engaging axial
end surface) defining a friction surface in selective contact with
a mating and co-facing friction surface of the clutch disc 216 to
close/couple the clutch of the brake-clutch unit 266. A clutch
spring 228 normally biases the two mating friction surfaces of the
clutch disc 216 and the rotor disc 218 apart from each other, for
example defining an axial space therebetween as shown in FIGS. 17
and 18, so that the clutch is open or decoupled and torque is not
transferrable from the input member 212 and the clutch disc 216 to
the rotor disc 218 and the output shaft 214. Electrical current
powering the clutch coil 208 causes the clutch disc 216 to be
attracted to the clutch coil 208 (right as shown) to overcome the
bias of the clutch spring 228 and close/couple the clutch by
bringing the friction surfaces of the clutch disc 216 and the rotor
disc 218 together. The clutch disc 216 may move alone or the input
member 212 may move with the clutch disc 216. Under circumstances
that the controller 96 determines that the motor 24 is to drive the
output shaft 40 through the brake-clutch unit 266 to perform a
powered opening or powered closing of the closure 50, the brake
actuator 204 is energized to release the brake (unless it is
already in the brake-released state) and concurrently the clutch
coil 208 is energized to close/couple the clutch and achieve the
drive state. This state of the brake-clutch unit 266 is maintained
throughout operation of the motor 24 to perform the powered opening
or the powered closing.
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